1. Field of the Invention
The present invention relates to a focal point detection device and a focal point detection method, and, particularly, relates to a focal point detection device and a focal point detection method which have a photographing lens including a focus lens, generate image data by receiving subject images pupil-divided through the photographing lens, and perform focal point detection using the image data.
2. Description of Related Art
There is known a focal detection device using a phase difference AF method which generates image data by receiving subject images pupil-divided through a photographing lens, performs correlation calculation using the image data, and obtains a phase difference to perform drive to a focusing position. In the phase difference AF method, it is difficult to perform phase difference AF detection in a state in which a defocus amount is large (largely blurred state). Accordingly, in a focal point detection device disclosed in Japanese Patent Laid-Open Publication No. 2010-139942 (in the following, called “Patent Literature 1”), a lens position is driven from a first position to a second position, and a drive direction is determined depending on a contrast evaluation value obtained at this time.
In the focal point detection device disclosed in above Patent Literature 1, it is possible to determine an appropriate focusing drive direction. However, in the determination of the drive direction, it is necessary to drive the lens position from the first position to the second position, which increases time for focusing. In particular, it takes a long time to perform the focusing of a subject such as a subject having a low contrast and a subject having a large defocus amount for which it is difficult to use the phase difference AF method.